Quantitative analysis of lung ultrasonography for the detection of community-acquired pneumonia: a pilot study

Abstract

Background and objective: Chest X-ray is recommended for routine use in patients with suspected pneumonia, but its use in emergency settings is limited. In this study, the diagnostic performance of a new method for quantitative analysis of lung ultrasonography was compared with bedside chest X-ray and visual lung ultrasonography for detection of community-acquired pneumonia, using thoracic computed tomography as a gold standard.

Methods: Thirty-two spontaneously breathing patients with suspected community-acquired pneumonia, undergoing computed tomography examination, were consecutively enrolled. Each hemithorax was evaluated for the presence or absence of abnormalities by chest X-ray and quantitative or visual ultrasonography.

Results: Quantitative ultrasonography showed higher sensitivity (93%), specificity (95%), and diagnostic accuracy (94%) than chest X-ray (64%, 80%, and 69%, resp.), visual ultrasonography (68%, 95%, and 77%, resp.), or their combination (77%, 75%, and 77%, resp.).

Conclusions: Quantitative lung ultrasonography was considerably more accurate than either chest X-ray or visual ultrasonography in the diagnosis of community-acquired pneumonia and it may represent a useful first-line approach for confirmation of clinical diagnosis in emergency settings.

Figure 1

Representative echo images (left) and frequency distribution of Gray scale units by quantitative analysis (right) for three patients with normal hemithorax (upper panels), subpleural (middle panels), and non-subpleural (lower panels) consolidations.

Figure 2

Mean echo intensity (Gray units) by quantitative lung ultrasonography from nonaffected (CT−) and affected (CT+) hemithoraxes with positive (LUS+) or negative (LUS−) results. CT: computed tomography; LUS: visual lung ultrasonography.